Updated

Syrian activists say Islamic State militants have launched an attack the last major Syrian military air base in the eastern province of Deir el-Zour.

The Local Coordination Committees activist collective and the Britain-based Syrian Observatory for Human Rights both reported the fighting for the airfield, which is just outside of the city of Deir el-Zour. Almost all of the surrounding province is under IS control.

The Observatory said Thursday that at least 19 government troops have been killed in the fighting, which began overnight with a suicide bombing on a Syrian military position near the air base. It said seven IS fighters have been killed.

The Local Coordination Committees and the Observatory both reported heavy clashes and government shelling on the villages surrounding the airfield.